Coated glass fiber strand



July 6, l1943. A. L slMlsoN COATED GLASS FIBER STRAND Filed Feb. 7, 1942 A INVENTOR Patented July 6, 1943 COATED GLASS FIBER STRAND Allen L. Simison, Newark, Ohio, assignor to Owens-Corning Fiberglas Corporation, a corporation of Delaware Application February 7, 1942, Serial No. 429.899

6 Claims.

The present invention relates to coatings for glass fibers particularly when grouped in strand or yarn form. This application is a continuationin-part of my copending application Serial Number 156,627, led July.31, 1937, now Patent No. 2,272,588, dated February 10, 1942.

It is the purpose of the present invention to provide coatings for glass bers that facilitate the formation of strands of the fibers, that assure ready fabrication of the strands into yarns and woven fabrics, and that improve the handleability of strands, yarns, and slivers and lend new properties to the finished article.

In the mechanical drawing method for the production of a plurality of extremely fine, long, continuous fibers, as, for example, by the method illustrated and described in the Slayter and Thomas Patent No. 2,234,986 dated March 18, 1941, it has been found that the speed of attenuation and production of fibers was limited by the speeds at which the fibers could be formed into strands and wound on packages in such a manner that the strands could be unwound and processed thereafter in the conventional textile machines. It is an object of the invention to provide a coating that permits glass fibers to be produced at extremely high speeds, as, for example, above 5,000 or even 20,000 feet per minute, and yet enable the fibers to be gathered into strand form and packaged into a useful article.

In this connection an important object of the invention is to provide a coating material which will be solidified and free from tackiness before it reaches the package. At extremely high speeds of about 5,000 to 10,000 feet per minute, the coatlng would have to substantially solidify in about 1/5 to 1/200 of a second after application. If the coating is not sufficiently solid by the time it reaches the package, the coating of one strand will tend to conflow with the coatings of adjacent strands on the package and thus bond the windings of the strand on the package to aunitary mass which cannot be unwound. It has been found that coatings requiring the volatilization of a solvent generally requires an excessive amount of time to solidify.

The present invention is also applicable to slivers of staple-type fibers made by the process of the Tucker and Lannan Patent No. 2,264,345, of December 2, 1941. In this process molten glass streams are attenuated by a gaseous blast and the fibers as they are formed are collected in a web which is elongated and narrowed into the form of a sliver. For some uses the sliver lacks sufficient integrity and handleability and the loose fibers and :ber ends are found objectionable.

One of the primary purposes of the 4coating itself is to bond the fibers together in strand form prior to twisting without fraying or subdividing. Once extremely fine fibers, that is, below .0004 inch and particularly below about .0002 inch in diameter, have been intertwisted into a thread, they will retain their coherence and strength without fraying or subdividing and without the necessity of an adhesive or coating material. Before twisting and when in strand form without proper adhesive, it is difi'icult to handle the strands and process them through the conventional textile machines.

It is a further object of the present invention to provide a coating for the fibers that will bind the fibers in the sliver and bind down loose fiber ends and facilitate subsequent fabricating operations such as twisting and weaving.

It is a further object to provide a strand of glass fibers wherein the individual fibers are provided with a coating which is sumciently .plastic and yielding to permit relative movement of lthe fibers in the strand, thereby preventing breaking of the fibers as the strand is twisted and woven or braided.

Another object of the coating material is to retain the loose ends of any broken fibers in the strand without permitting them to break away and form a fuzz. This feature is particularly important when attempting to unwind a strand from a wound package thereof, owing to the fact that a loose fiber continues to break away from the main body of the strand as it is unwound and produces a fuzz around the package as the loose fiber is broken by the subsequent unwindings of the main body of the strand. This causes other fibers to be broken away from the strand until the package is destroyed.

Another object of the invention is to provide a coating substance which will readily distribute itself uniformly over the fibers at extremely high speeds.

Another important object of the invention is to provide a. strand of glass fibers coated with a substance that is readily removable from the strand at any stage of the fabrication, that is,

after twisting, weaving, braiding, knitting, or the like. After the fibers have been fabricated into the finished product, it is sometimes desired to remove all or substantially all of the organic substances therefrom in order to produce a pure, wholly inorganic material which is reproof, rotproof, waterproof, etc.

Coating substances requiring expensive solvents or a lenghty process of removal are not desirable owing to the increased cost of fabrication and processing of the material. A large number of previously employed coatings required application in water solutions or admixed with water which is disadvantageous since the surfaces of newly formed glass bers seem to display high afnity for water and when wet have a marked decrease in resistance to mutual abrasion. Further, solvents require some special drying treatment or other provision therefor and are objectionable therefore in many cases as an added cost factor.

It is a further object of the present invention to provide a coating for glass fibers that requires no solvent or other vehicle for application, thereby obviating the above difllculties.

Other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the drawing, in which:

Fig. ll is a diagrammatic elevational view shown partly in section of an apparatus for attenuating a multiplicity of fine glass fibers of substantially continuous lengthl grouping them in strand form, and applying a coating thereto in accordance with the present invention; and

Fig. 2 is a diagrammatic elevational end view shown partly in section of apparatus for attenuating glass fibers and converting the fibers into slivers.

I have discovered that the foregoing objects are realized if the individual fibers in the strand are provided with a coating of thermoplastic substances, as for example, esters of high atomic alcohols, such as waxes. These serve admirably as coatings for the individual ne glass filaments and enable the production and fabrication thereof to be carried on at speeds far higher than those used heretofore.

Various waxes maybe used as, for example, cerese wax, mineral waxes, paramn wax, carnauba wax, Japan wax, vegetable waxes, beeswax, or the like or mixtures thereof. The waxes are applied in a molten condition, generally in the neighborhood of about 120 F. to 190 F. In

` melted form, the waxes may be applied by any suitable means such as a pad. groove, roller, or other suitable methods. The glass strands are passed through the molten wax, or films thereof, picking up the proper amount, and then are passed through a cooler zone which freezes the wax almost instantaneously and produces a firm, flexible, coherent strand which may easily be wound upon a package. In winding the strands over a package, it is preferable to traverse the strand as it is being wound in order to wind the strand uniformly and evenly and in a manner which facilitates easy unwinding.

While, as brought out hereinabove, various waxes may be used, it is preferable to use a wax which is slightly plastic at room temperature although not too soft and tacky. If the wax is too stiff and brittle at room temperature, or temperatures at which the package is used, the wax tends to convert the strand into a solid, stiff rod which is frangible and easily breaks on bending or slight twisting. On the other hand, if the wax is too soft, it will tend to be too tacky or sticky on the package and during fabrication, and thus will prevent easy and smooth unwinding of the strand from the spool, and, during manipulation of the strand, the wax thereon will tend to accumulate on eyes or other objects with which the strand comes in contact.

In this connection, it has been found preferable to provide waxes having melting temperatures in the range of about F. to 170 F., although variations from this range are permissible owing to the fact that the important properties of plasticity, softness and freedom from tackiness, should be at room temperature.

'Ihe wax is generally applied in amounts, which, in comparison with the weight of the filaments, are within a range of about 5 to 25 per cent, although preferably in the neighborhood of about 10 to 15 per cent depending on the fiber diameter and the number of fibers in the strand. In standard practice about 12 per cent is generally applied. If too little wax is used, the fibers in the strand are not held sufficiently firmly together, and vibration or other action of the machine may tend to separate the strands into two or more smaller ones. If. on the other hand, too much wax is applied, there will be a tendency toward the formation of beads along the strand, which are undesirable and prevent manipulation and proper handling of the strand.

Referring now to the drawing and particularly to Fig, 1, reference character I0 designates a refractory furnace having an inner lining in the form of a V-shaped trough Il, preferably made of platinum or platinum alloy and containing a body of molten glass. A series of outlet openings l2, having diameters of about .025 to .08 inch, are provided at the lower portion thereof at the convergence of the sides of the trough il. Small glass streams flowing from the orifices are attenuated by means of a drum I3 on which the filaments are wound.

Arranged below the furnace a suitable distance is one or more grouping and Waxing devices f5 adapted to draw the individual filaments together into a strand form and simultaneously apply a wax coating thereto. Ordinarily one waxer I5 is sufficient, but at extremely high speeds it has been found advantageous to use a plurality, each providing a light coating.

After the fibers have been grouped and suitably coated with a waxing material, the wax is solidifled rapidly by cooling to form a unitary strand and is then wound over the revolving drum I3. In winding the strand upon the drum, it is desirable to traverse the yarn by means of the traverse I9 in order to form a uniform, easily unwindable package.

The waxer I5 comprises a receptacle 20 into which wax is placed. Heating means 22 such as an immersion type heater is located in the receptacle to melt the Wax and maintain its fluidity. The wax is fed from the container 20 through a suitable orifice onto a platen 21 which may be covered along the upper portion thereof with a pad of felt or flannel or other cloth upon which the molten wax drips, maintaining the pad in a saturated condition. A suitable heating means electrically connected to a current source 30 may be mounted in the platen 21. serving to maintain the wax at the proper temperature as it is being applied.

The glass filaments orv fibers emerging from the bushing orifices i2, are individually drawn over the saturated felt pad and are each coated with a thin lm of molten wax. and are then grouped together and compacted into strand form.

Fig. 2 depicts apparatus for producing stapletype bers and forming the bers into a sliver.

a plurality of feeding orifices in its bottom wall.

A blower 38 directs gaseous blasts onto the streams of glass issuing from the orifices in the bushing to attenuate the streams into fibers.

to rise as a scum to the surface of the wash solution.

In order to quicken even further the removal t process. it is possible to apply various emulsify- The fibers are conveyed by the gaseous blasts Y and deposited on a collecting surface 39 on a rotatable drum 40 spaced beneath the blower. The fibers build up into a web or mat of tangled interlaced b'ers on the surface 39 and this web is drawn off the surface in the direction of movement of the surface by a winding drum 42. As it is drawn the web is elongated to the desired sztent to produce a sliver in which the bers extend predominantly lengthwise of the sliver but are interlaced sufllciently to hold together in a compact strand.

As the fibers travel toward the collecting surface, wax in molten form or, less desirably, in the form of an aqueous emulsion, is sprayed onto the moving fibers, for example, by means of a spray gun M directed across the path of the blastborne fibers. The individual fibers are thus coated with a uniform film of wax which aids in relative movement of the fibers as the web is narrowed and elongated and also decreases abrasion and consequent breakage of the fibers. It also aids .in holding the fibers together ln the sliver.

Where desired, the wax may be applied to the sliver in the space between the collecting Surface and the winding drum by means of an applicator similar to the platen 21 or by being sprayed onto the sliver. i l

After the drums I8 and 40 have been filled and covered with packages composed of glass strands, they may be removed and the strands thereon processed through the subsequent desired textile machines such as twisters, winders, or looms. During these subsequent operations, the wax serves to hold the individual fibers or filaments within the strand, in spite of the fact that they are laid in parallel relationship and have no twisting, .and in spite of the fact that in the case of continuous filaments various ends or individual filaments may have been broken, for example, during the attenuation and forming process.

.After the strands have been fabricated into the finished product, as, for example. in a woven, knitted, braided, or otherwise interlaced glass fabric, the relatively soft wax surrounding each fiber conditions the fibers to provide a soft. supple fabric that is smooth and lustrous. The good electrical properties of the wax also make the fabrics well suited to electrical insulation and the moisture repellent nature of the wax adapts the fabrics to uses where high humidity and other moisture conditions prevail. The present coating materials are thus better suited for many ap,- plications than those heretofore used and which were usually hard and brittle if moisture resistant, for instance, convertible resins, or if solt and plastic lacked the desired moisture resistance, for instance, gums and plasticized starch. The few materials that may have combined the properties of the present materials could normally be applied only in solvents.

If the present coating is objectionable for some uses because it detracts from the inorganic properties of the fabricated products it may be readily removed after it has served its purpose in facilitating fabrication. This may easily be done by a rapid washing of the fabric in a soap solution. The soap readily emulsifles the wax and causes it ing agents to the wax such as triethanolamine, bentonite, soaps, etc. `Triethanolamine is preferable owing to the fact that only a small amount of it is necessary for emulsifying purposes.

It is to be observed that the wax performs the function of lubricating the individual filaments during the fabrication process. As the strand is twisted into threads. yarns, or cables, and the threads interwoven or interlaced with other threads or yarns, the individual filaments tend to rub over one another and scratch each other to their mutual destruction. The coating of wax, not only over the strand but also interjacent the fibers, serves to minimize this effect and lubricates the fibers from one another whereby they may slip past one another without fracturing or scratching each other.

Where the coating on the fibers is intended as permanent, I have found it advantageous to incorporatein the wax a cationic-active material of the primary, secondary or tertiary type and one that will dissociate in water to form a positive radical containing a carbon group of more than eight carbon atoms and preferably twelve or more. The materials preferred are of the general formula, (R)-Z-X, where X is the anion, either organic or inorganic, Z is nitrogen, phosphorus.

atoms and attached to Z by a carbon bond.r

Stearyl or cetyl monoamine hydrochloride or acetate, trimethyl stearyl or cetyl ammonium bromide, octadecyl trlmethyl ammonium bromide, dodecyl pyridinium sulfate, and similar materials have been found satisfactory. Sulfonium and phosphonium compounds such* as methyl benzyl stearyl sulfonium methyl sulfate and triamyl phosphonium cetyl bromide may also be used. These materials greatly increase the lubricating properties of the wax especially in the presence of moisture and serve also to make the lubricating effect of the wax coating more lasting.

The cationic-active materials are preferably added in small amounts up to about 1 to 3 per cent more or less of the wax, by melting the wax and stirring in the material. Should the wax be applied to the bers as an aqueous emulsoin the cationic-active material in addition to serving as an adjuvant to the wax will act as an emulsifying agent providing a stable emulsion.

Modifications and variations may be resorted to within the scope and spirit of the present invention as dened in the appended claims.

'I claim:

1. A strand composed of a multiplicity of long, fine, attenuated glass fibers, and a coating of wax on the individual fibers in amount sufllcient to bond the individual bers together in strand crm.

2. A strand composed of a multiplicity of fine glass bers, and a coating thereover comprising a wax which is slightly plastic and free from tackiness at room temperature.

3. A strand comprising a multiplicity of extremely fine glass fibers and a coating material forming a coating for the individual fibers and also forming a coating for the surface of the strand as a whole, said coating material being wlaxo 1raving a melting point between 150 and 4. A strand comprising a multiplicity of long,

4 2,328,694. extremely flne glas bers and bonding material to permit relative consisting ot wax forming a. coating over the surhaving admlxed therewith faces of the individual nbers and also a coating cationic-active for the strand as a whole, said wax being present 6. A etrlnd m amount mmcient w bum the aber; together 5 une, attenuated glmnber's e and reeem ehem m the ferm of e emma wnne bending :wenn eveffui theme1- mbneetmg lthe aber eurreeee ma preventing a1- vmuu aber mmeeem rect contact or the bers with each other. the fibers together in 5. A strand composed of a. multiplicity of long, material compsinz a nne, attenuated glass ilbers, and a coating of wax 1o sifyinl agent torthef Vix, over the smeees or the individuel obere m be reeduy removed :minethegnberi amounts serving t0 bund the individual bers t0- Y L j 'l gether m strand form and to lubricete the nbers Anni n. mon. 

